As a lens that magnifies an image of an observation object, a solid immersion lens (SIL: Solid Immersion Lens) is known. A solid immersion lens has a hemispherical shape or a hyperhemispherical shape called Weierstrass sphere, that is a microlens of about 1 mm to 5 mm in size. Then, provided that the solid immersion lens is installed so as to be made to contact closely with the surface of an observation object, its numerical aperture (NA) and magnification are both magnified, which enables an observation with high spatial resolution.
As a solid immersion lens holder that holds such a solid immersion lens, for example, a holder disclosed in Patent Document 1 is known. The solid immersion lens holder disclosed in Patent Document 1 is coupled to a front end of an objective lens via an arm member, that is configured to hold a solid immersion lens on the front surface side of the objective lens.    Patent Document 1: International Publication No. 2005/043210 Pamphlet